fix(desktop): carry typed OAuth failure reasons from main-process producers

[orangeCatDeveloper]

Summary

subscriptionResultMessage localized OAuth login failures by matching English Host prose with regexes. One of the three regex families — did not present OAuth|no matching OAuth presentation — described failures Desktop produces itself: the presentation timeout and the absent-request throw in runtime-host-oauth-presentation.ts. Matching your own prose is a contract you cannot see break; rewording either sentence silently drops the branch.

Those producers now throw a typed OAuthPresentationError, and get-auth-url maps it alongside the Host's operation codes onto the failure envelope:

• operation_conflict → login_in_progress
• OAuthPresentationError → presentation_failed
• operation_unavailable → experimental_disabled (unchanged)

The renderer catalog maps the two new reasons per locale and the presentation regex is deleted. The enrollment is disabled and already in progress prose fallbacks stay: the first covers Hosts older than these codes, and the second still has a live producer in presentation.expect, which throws a plain error. The ad-hoc loginConflict / browserPresentFailed keys fold into resultCodes with the same wording.

Refs #2672

Verification

apps/desktop full dist suite        2489 pass / 0 fail
apps/desktop typecheck (4)          0 errors
renderer architecture ratchet       passes against the base
npm run format:check                clean

Not run: Electron e2e against a live Host login flow.

AI use

• Generative tooling made a substantive contribution

Tool(s) and scope: Claude Code — traced the producer→presenter path, implemented the typed error and reason mapping, removed the regex, added the tests, and wrote this description.

Checklist

• Tests cover the change and fail without it
• Lint, format, typecheck and the affected suites pass locally

Does this PR entail a change in behavior?

• Yes — login-conflict and browser-presentation failures render catalog copy through typed reasons instead of English prose matching.